Based on the shallow-basin theory that was brought up by American scientist Hazen in 1904, inclined plate sedimentation tank, inclined tube sedimentation tank and labyrinth sedimentation tank were successively developed, and their structure were designed as much close as an ideal sedimentation tank. However, these sedimentation tanks mentioned above (including same-directional, counter-directional, and transverse directional sedimentation tank) are characterized by following disadvantages:
Firstly, flowing water needs to change its direction when through the inclined tube or inclined plate (same-directional, counter-directional), thus leads to water state variation and is harmful to the suspension sedimentation.
Secondly, the process of water flowing through inclined tube or inclined plate has a washing and disturbing effect on sedimentary suspension, which would probably be re-agitated by water flowing and causes reversible sedimentation.
Thirdly, two triangle dead zones would be formed when the inclined tube (inclined plate) are installed as components, which causes decreased usage rate of the sedimentation tank and reduced area of flowing water.
The above defects of current sedimentation equipments significantly constrict their sedimentary capacity and impair the clarification effect.